[PATCH -mm] capabilities: reset current->pdeath_signal whenincreasing capabilities

[Serge E. Hallyn]

I think the following does the right thing with respect to the
pdeath_signal bug and file capabilities.  I somewhat question the need
to do this if we're just switching uid or gid (if running in strict
capability mode), but it seems prudent to just leave it right there.

Note that so far this is only need in -mm.  Linus' tree will do the
right thing with the original pdeath patch since the only way to
increase capabilities is to first become root or run a setuid root
binary.

thanks,
-serge